Cumulative Curve. -- A curve in which each value, except the first which is zero, is a total or accumulation of all preceding values.

Curve Chart -- A chart in which a line is plotted on a grid.

Dependent Variable. -- The data presented in a chart or table which varies according to a change in the independent variable. The amount scale on a time curve chart is the dependent variable.

Disc Chart. -- See circle chart.

Distorted Map. -- A map in which the areas of states, countries, etc., are proportional to quantitative data.

Divided Circle. -- See sector chart.

Dot Map. -- See statistical map.

Extrapolation. -- Projection of the data beyond known points.

Flow Chart. -- Graphic representation of movements geographically or through an organization or structure.

Flow Map. -- A map in which either or both qualitative and quantitative flow of goods, persons, automobiles, etc., is shown.

Form. -- One side of a printed sheet.

Frequency Chart. -- A chart in either bar or curve chart form showing distribution of items according to kind, size, location, or time of occurrence.

Gantt Chart. -- A specialized type of production chart. See progress chart.

Geneology Chart. -- A chart used as a method of showing ancestry and heredity traits.

Genetics Chart. -- See geneology chart.

Graphic Narrative. -- A story told by means of pictures.

Grid. -- The surface or field composed of coordinate rulings on which data are plotted or graphed.

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Guide Map. -- A detailed map on which highways, railroad routes, or other methods of transportation are indicated together with cities, etc. Sec route map. Gun-Shot Chart. -- See scatter chart.